Acetylene (C2H2) is widely used as a combustion gas in gas cutting, gas welding, brazing or the like. Acetylene is superior in combustion speed and combustion intensity, and thereby preferable as the combustion gas.
However, when acetylene undergoes storage, transportation or the like in a state of compressed gas, an explosive decomposition is likely to occur. Therefore, acetylene is stored or transported in a state of being dissolved in a solvent such as acetone or dimethylformamide, which in turn makes acetylene unsuitable for mass transportation in collective containers or large scale containers.
In this regard, there is suggested a proposal to use a mixture gas of ethylene at 20 to 80 v/v % and hydrogen at 80 to 20 v/v % as a substitute gas for acetylene. Thereby, it is considered possible to obtain such advantageous effects as improved safety in a ship-bottom maintenance operation or a pit maintenance operation due to rapid diffusion of the mixture gas into atmosphere, combustion performance similar to acetylene, low price, and easy storage and transportation thereof (for example, see Japanese Patent Laying-Open No. 53-118401 (PTD 1)).